Method for operating a combined cycle power plant

Abstract

A method for operating a combined cycle power plant, according to which shortly before the planned start-up of a parked load, the steam turbine is lowered to a very low output, the gas turbine is then operated in parked load, and next the steam turbine is powered up to a parked output. The GT operating power can be the rated power of the gas turbine. The ST operating power can be the rated power of the steam turbine.

1 . A method for operating a combined cycle power plant, comprising:
 operating the gas turbine at a GT operating power and operating the steam turbine at an ST operating power,   reducing the power of the steam turbine to an ST part power, wherein the ST part power is lower than the ST operating power,   reducing the power of the gas turbine to a GT parked power, wherein the GT parked power is lower than the GT operating power,   wherein once the GT parked power of the gas turbine has been reached, increasing the power of the steam turbine to an ST parked power.   
     
     
         2 . The method as claimed in  claim 1 ,
 wherein the ST part power is 5%-40%, 5%-30%, 5%-20%, or 5%-10% of the ST operating power.   
     
     
         3 . The method as claimed in  claim 1 ,
 wherein the GT parked power is 20%-60% of the GT operating power.   
     
     
         4 . The method as claimed in  claim 1 ,
 wherein the ST parked power is 20%-60% of the ST operating power.   
     
     
         5 . The method as claimed in  claim 1 ,
 wherein the power of the steam turbine is reduced by reducing the pressure of the steam.   
     
     
         6 . The method as claimed in  claim 1 , wherein the steam turbine comprises a HP, IP and LP turbine section and
 wherein the HP turbine section, the HP turbine section and the IP turbine section, the IP turbine section, the IP turbine section and the LP turbine section or the LP turbine section is/are not charged with steam.   
     
     
         7 . The method as claimed in  claim 6 ,
 wherein the pressure of the steam in the turbine sections not charged with steam is reduced to below a limit value.   
     
     
         8 . The method as claimed in  claim 1 ,
 wherein the drain, evacuation lines, start-up lines or process steam lines are opened.